Your 45th wedding anniversary symbol is sapphire, which is the stone for loyalty and fidelity, a pretty apt gift for 45 years together as husband and wife.
Sapphires hold their place in legend, it is the legend that Helen of Troy had a star shaped sapphire that was believed to hold the key to her desirability. Early sailors believed that it would protect them from drowning and there are no end of cures that sapphires can help with from fevers to thyroid problems and many, many others.
But there is no getting away from the fact that Sapphires are beautiful and there are so many colors that you can choose from; blue, pink, gold/yellow are more popular and then you also have the rarer colors of green, magenta, brown and violet. There are two distinct types of sapphires, you can buy natural sapphires these are more expensive or simulated sapphires that are generally cheaper. Simulated sapphires are ones that are created in a laboratory but don't let that put you off as they do look lovely.
Using the colors of sapphires is also a great theme for your 45th anniversary party. Just think what a room would look like with beautiful blue decorations. Plus it's a great color for a new dress! Or jeans are a great sapphire blue if you want to have a more relaxed party.